ombi: adopt the Plex entry that plex itself answers for

ace's ombi holds one Plex entry, loaded from an older server and later
retyped to plex's public name: its stored machineIdentifier is not plex's,
while its address answers as plex. Matching by identifier alone would leave
it and add a second entry for the same server.

When no entry carries the server's identifier, each entry's own address is
asked for /identity, and an entry plex answers for is adopted: the bound
connection laid over, and the identifier corrected (ombi builds its "view in
Plex" links from it). Its name, libraries and every other choice stay. An
entry that cannot be asked, or answers as another server, is left alone;
nothing is guessed. Every call of the step is now bounded, since an entry may
name a host that no longer answers.

modules/ombi/plex/settings.ts

@@ -9,12 +9,20 @@
 // **Which entry is plex's.** ombi may list several Plex servers. The one this provision names is
 // found by the server's own machineIdentifier, which plex answers at /identity — the same value
 // ombi stored when an operator loaded the server in its settings screen. That entry's connection is
-// brought in line; an entry for any other server is never touched. When no entry is this server's,
-// one is added, named as plex names itself — it is the mesh's, so later runs keep it true.
+// brought in line; an entry for any other server is never touched.
 //
-// **Only the connection, and only when it differs.** Host, port, TLS, base path and token. Whether
-// Plex is enabled in ombi, watchlist import, the selected libraries, the batch size and everything
-// else an operator chose are left exactly as they are.
+// When no entry carries that identifier, an entry may still be this server reached another way:
+// ace's ombi holds one loaded from an older server and later retyped to plex's public name, so its
+// stored identifier is stale while its address answers as this plex. Each entry's OWN address is
+// asked for /identity, and an entry plex itself answers for is this server's — adopted: its
+// connection laid over and its identifier corrected (ombi builds its "view in Plex" links from it).
+// Nothing is guessed: an entry whose address is unreachable, or answers as another server, is left
+// as it was. Only when no entry is this server's either way is one added, named as plex names
+// itself — it is the mesh's, so later runs keep it true.
+//
+// **Only the connection, and only when it differs.** Host, port, TLS, base path and token — and the
+// identifier of an adopted entry. Whether Plex is enabled in ombi, watchlist import, the selected
+// libraries, the batch size and everything else an operator chose are left exactly as they are.
 //
 // **A token plex refuses is never written.** Until the operator accepts the server's token for this
 // pair, the mesh delivers a value it minted itself, which plex answers with 401 (or 400 on its own
@@ -116,8 +124,10 @@ export async function plexTakes(http: Http, want: PlexConnection): Promise<{ tak
 }
 
 /** The server's own machineIdentifier, which plex answers without a token. */
-export async function plexIdentity(http: Http, want: PlexConnection): Promise<string> {
-  const res = await plexGet(http, want, "/identity", false);
+export async function plexIdentity(http: Http, want: Pick<PlexConnection, "ip" | "port" | "ssl" | "subDir">): Promise<string> {
+  const host = want.ip.includes(":") && !want.ip.startsWith("[") ? `[${want.ip}]` : want.ip;
+  const base = `${want.ssl ? "https" : "http"}://${host}:${want.port}${want.subDir ? `/${want.subDir.replace(/^\/+|\/+$/g, "")}` : ""}`;
+  const res = await http.fetch(`${base}/identity`, { method: "GET", headers: { Accept: "application/json" } });
   if (res.status !== 200) throw new Error(`plex answered ${res.status} at /identity`);
   const body = JSON.parse(await res.text()) as { MediaContainer?: { machineIdentifier?: unknown } };
   const id = body.MediaContainer?.machineIdentifier;
@@ -138,25 +148,57 @@ export function plexAcceptRemedy(from: string): string {
 /** The batch size ombi's settings screen fills in for a server it adds ("150 by default"). */
 const EPISODE_BATCH_SIZE = 150;
 
+/** ombi's server entries, as its settings document holds them (null on a fresh ombi). */
+export function serversOf(document: Record<string, unknown> | undefined): Record<string, unknown>[] {
+  const servers = document?.servers;
+  return Array.isArray(servers) ? (servers as Record<string, unknown>[]) : [];
+}
+
+/**
+ * Which entries, holding another identifier, plex answers for at their own address — this server,
+ * reached another way. Asked only when no entry carries the identifier. An entry that cannot be
+ * asked is not this server's: nothing is guessed.
+ */
+export async function answeringAs(http: Http, servers: Record<string, unknown>[], machineIdentifier: string): Promise<Set<number>> {
+  const out = new Set<number>();
+  if (servers.some((s) => s?.machineIdentifier === machineIdentifier)) return out;
+  for (const [i, s] of servers.entries()) {
+    const ip = typeof s?.ip === "string" ? s.ip.trim() : "";
+    const port = Number(s?.port);
+    if (!ip || !Number.isInteger(port) || port <= 0 || port > 65535) continue;
+    const subDir = typeof s.subDir === "string" && s.subDir.trim() !== "" ? s.subDir : null;
+    try {
+      if ((await plexIdentity(http, { ip, port, ssl: Boolean(s.ssl), subDir })) === machineIdentifier) out.add(i);
+    } catch {
+      // unreachable, or not a plex: not this server's
+    }
+  }
+  return out;
+}
+
 /**
  * ombi's Plex settings with this server's connection laid over them: every entry naming the
- * server's machineIdentifier gets the connection, every other entry is left as it was, and when
- * none names it one is added. Returns the document to save and the fields that changed.
+ * server's machineIdentifier — or adopted, its address answering as this server — gets the
+ * connection (an adopted one also the identifier), every other entry is left as it was, and when
+ * none is this server's one is added. Returns the document to save and the fields that changed.
  */
 export function withPlexServer(
   document: Record<string, unknown> | undefined,
   machineIdentifier: string,
   want: PlexConnection,
   name: string,
+  adopted: ReadonlySet<number> = new Set(),
 ): { next: Record<string, unknown>; fields: string[]; added: boolean; entry: Record<string, unknown> } {
   const doc = document ?? {};
-  const servers = Array.isArray(doc.servers) ? (doc.servers as Record<string, unknown>[]) : [];
+  const servers = serversOf(doc);
   const fields = new Set<string>();
   let entry: Record<string, unknown> | undefined;
-  const next = servers.map((s) => {
-    if (s?.machineIdentifier !== machineIdentifier) return s;
+  const next = servers.map((s, i) => {
+    const adopt = adopted.has(i) && s?.machineIdentifier !== machineIdentifier;
+    if (s?.machineIdentifier !== machineIdentifier && !adopt) return s;
     for (const f of differingPlex(s, want)) fields.add(f);
-    const laid = { ...s, ip: want.ip, port: want.port, ssl: want.ssl, subDir: want.subDir, plexAuthToken: want.plexAuthToken };
+    if (adopt) fields.add("machineIdentifier");
+    const laid = { ...s, machineIdentifier, ip: want.ip, port: want.port, ssl: want.ssl, subDir: want.subDir, plexAuthToken: want.plexAuthToken };
     entry ??= laid;
     return laid;
   });
@@ -201,7 +243,8 @@ export async function reconcilePlex(http: Http, ombi: Ombi, binding: Binding | u
 
   try {
     const document = (await ombiCall(http, ombi, "GET", "/Settings/Plex")) as Record<string, unknown> | undefined;
-    const laid = withPlexServer(document, machineIdentifier, want, name);
+    const adopted = await answeringAs(http, serversOf(document), machineIdentifier);
+    const laid = withPlexServer(document, machineIdentifier, want, name, adopted);
     if (laid.fields.length > 0) {
       const saved = await ombiCall(http, ombi, "POST", "/Settings/Plex", laid.next);
       if (saved === false) return { app, result: "refused", problem: "ombi declined to save its Plex settings" };